A continuing goal of semiconductor device fabrication is to conserve semiconductor wafer real estate (in other words, to achieve high integration) while maintaining integrity and desired performance characteristics of semiconductor devices. Such has led to development and improvement of various semiconductor constructions, including, for example, recessed access devices (RADs), and partial silicon-on-insulator (partial-SOI) constructions.
Another goal of semiconductor device fabrication is to apply semiconductor fabrication technologies to development of a diversity of microstructures. Such has led to development of optical waveguides fabricated in semiconductor materials; and to development of micro-electro-mechanical systems (MEMS).